An exonucleolytic activity of human apurinic/apyrimidinic endonuclease on 3' mispaired DNA

Human apurinic/apyrimidinic endonuclease (APE1) is an essential enzyme in DNA base excision repair that cuts the DNA backbone immediately adjacent to the 5' side of abasic sites to facilitate repair synthesis by DNA polymerase beta (ref. 1). Mice lacking the murine homologue of APE1 die at an early embryonic stage. Here we report that APE1 has a DNA exonuclease activity on mismatched deoxyribonucleotides at the 3' termini of nicked or gapped DNA molecules. The efficiency of this activity is inversely proportional to the gap size in DNA. In a base excision repair system reconstituted in vitro, the rejoining of nicked mismatched DNA depended on the presence of APE1, indicating that APE1 may increase the fidelity of base excision repair and may represent a new 3' mispaired DNA repair mechanism. The exonuclease activity of APE1 can remove the anti-HIV nucleoside analogues 3'-azido-3'-deoxythymidine and 2',3'-didehydro-2', 3'-dideoxythymidine from DNA, suggesting that APE1 might have an impact on the therapeutic index of antiviral compounds in this category.     

Global analysis theory of climate system and its applications

The idea and main theoretical results of the global analysis theory of climate system are briefly summarized in this paper. A theorem on the global behavior of climate system is given, i.e. there exists a global attractor in the dynamical equations of climate, any state of climate system will be evolved into the global attractor as time increases,indicating the nonlinear adjustment process of climate system to external forcing. The different effects of external forcing, dissipation and nonlinearity on the long-term behavior of solutions are pointed out, and some main applications of the global analysis theory are also introduced. Especially, three applications, the adjustment and evolution processes of climate, the principle of numerical model design and the optimally numerical integration, are discussed.     

Construction of a novel economy-climate model

An attempt has been made to construct a novel economy-climate model by combining climate change research with agricultural economy research to evaluate the influence of global climate change on grain yields. The insertion of a climate change factor into the economic C-D (Cobb-Dauglas) production function model yields a novel evaluation model, which connects the climate change factor to the eco-nomic variation factor, and the performance and reasonableness of the novel evaluation model are also preliminarily simulated and verified.     

SiAlON材料的氧化行为

SiAlON材料在高温氧化气氛下的氧化行为和氧化机理一直是材料科学领域关注的焦点.本文综述了SiAlON材料氧化的相关研究,分析对比了单相和复相SiAlON材料的氧化行为,讨论了SiAlON材料的氧化影响因素以及氧化机理,指出了SiAlON材料氧化研究存在的问题.     

老年肺炎214例临床分析

目的 :了解老年肺炎发病情况及临床特点。方法 :对 2 14例老年肺炎的发病季节、临床症状、实验室检查和治疗进行分析。结果 :本地区老年肺炎夏季发病有增多趋势 (2 9% )。老年组与老年前期组相比 ,发热、胸痛少 ,但精神神经症状、消化道症状、心律失常明显 ,白细胞计数和嗜中性粒细胞分类不高。结论 :本地区老年肺炎临床表现不典型     

Tunable fabrication of single-crystalline CsPbI3 nanobelts and their application as photodetectors

Lead halide perovskites have received increasing attention recently as a candidate material in various optoelectronic areas because of their high performance as light absorbers. Herein, we report the growth of CsPbI3 nanobelts via a solution process. A single-crystalline CsPbI3 nanobelt with uniform morphology can be achieved by controlling the amount of PbI2. A single-crystalline CsPbI3 nanobelt possesses a mean width, length, and thickness of 100 nm, 5 μm, and 20 nm, respectively. In this work, photodetectors (PDs) based on individual CsPbI3 nano-belts are constructed and found to perform well with an external quantum efficiency and responsivity of 2.39 × 105％ and 770 A/W, respect-ively. The PDs also show a high detectivity of up to 3.12 × 1012 Jones, which is at par with that of Si PDs. The PDs developed in this work ex-hibit great promise in various optoelectronic nanodevices.     

Testing for the usefulness of forecasts

Ashley (Journal of Forecasting 1983; 2 (3): 211–223) proposes a criterion (known as Ashley's index) to judge whether the external macroeconomic variables are well forecast to serve as explanatory variables in forecasting models, which is crucial for policy makers. In this article, we try to extend Ashley's work by providing three testing procedures, including a ratio‐based test, a difference‐based test, and the Bayesian approach. The Bayesian approach has the advantage of allowing the flexibility of adapting all possible information content within a decision‐making environment such as the change of variable's definition due to the evolving system of national accounts. We demonstrate the proposed methods by applying six macroeconomic forecasts in the Survey of Professional Forecasters. Researchers or practitioners can thus formally test whether the external information is helpful. Copyright © 2010 John Wiley & Sons, Ltd.     

可裂G2的类似Iwasawa分解的某些投影

给出了线性连能单李群可裂Ｇ２的类似Ｉｗａｓａｗ分解的某些投影,这对进一步给出可裂Ｇ２的缠结算子作用于某些标准诱导表示的子空间的公式十分必要的。     

三维全内反射荧光光谱法研究细胞色素C在银电极表面的吸附特性

利用现场三维全内反射荧光光谱法研究了细胞色素Ｃ在不同电极表面的吸附特性,发现与细胞色素Ｃ溶液的荧光峰峰位相比,吸附在裸露银电极表面的细胞色素Ｃ的荧光峰峰位发生蓝移,表明埋在细胞色素Ｃ多肽链内血红素的暴露面积减少,而使细胞色素Ｃ的电化学反应不可逆。当细胞色素Ｃ吸附在促进剂修饰的银电极表面时,其荧光峰峰位基本上不发生蓝移,表明血红素的暴露面积基本上不减少,而能观察到细胞色素Ｃ准可逆的电化学反应。